Nifty little circuit, I can see some ways to use this one! Keep the circuit small and it will fit under the back of my bike seat, a great attention getter tail light for night rides. A buddy here wants one made with slightly brighter LEDs for the end of his boat dock. On a dark lake, the ripple of light will make finding his dock a cinch! I'll build that one in April, and run it from a battery pack and recharge with a small solar cell array.